Improvement in clamps



all whom it may Cincinnati, Hamilton county,

,back and forth,

. preferably of cast-iron,

`sides and bottom of the thick. i

MATHIAS G, BURKHARDT, OF CINCINNATI, GHIO.

Y Letters Patent No. 97,872, lated December 14, 1869- IMPROVEMENT `IN' CLAMPS.

The Schedule referred to inethese Letters Patent and making part of theeeinie.

concern: Be it known that I, Munras G. BURKHARDT, of

State of 0hio, have'invented a certain new and useful Improved Clamp, for foundry4 and other mechanical uses; and Il hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this specification.

The nature of my invention consists in construct- "ing a clamp with al rectangular head, peculiarly-constructed jaws, connected to grooved arms, to slide to 'clutch crloosen the clamps, and using a right-handed and left-handed screw-rod, to contract and expand fthe jaws. I

i These jaws slide sufficiently `loose in their head to have but little friction, while the several sides and "bearings of the frame serve to stiften the clamps, and' relieve the jaws and screw-rod from strain.

"In the accompanying drawings, illustrative of my t eration.

`A is the frame or bed, which 'is a rectangular box, thesides of .which .are of' sufticient thickness to impart the necessary amount of strength. i

'.lhe cap or cover B is fastened on substantially .as shown.

I usually make theexterior of the box' A two and three-quarter inches deep by twoinolxes wide, and the same about one-quarter inch C Gf are` jaws, the shanks I) D of which have grooves E E on the under side, and` projections F F', whichflatter rest on the bottom ofthe box A, and slide easily between the sides of the same. l

G isan iron rod, with a right and left-hand screw cut or chased upon it, meeting in the middle, and eri- V firmly fastened inthe proper position.

ble of sliding They lit in between the bearings a a of the box.,

and prevent the rod G from working backward and forward in the bed.

lhe ends of the rod G journal in bearings a, a, and protrude through the ends of the bed suliciently to provide for the attachment of a common wrench, which serves to revolve `the rod and expand or contract the jaws. v f

The sides ofthe grooves E E `rest upon the en ds of the box A, and the projections F F upon the bottom of the same, the sidesof the shanks I) D at the same time ttin g the' sides Vof the box and against the cover B, so that while the jaws are at any time capaeasily within the box, they are fully supported at all points when `in action.

The provision of the mediately under y:the jaws.

It is obvious that byreversing the jaws C C', and forming theprojectious F at the jaw-end of the Shanks, the device can `be used as a clamp and vise both.

By the lprovision ofthe rightfand left-hand screw on the rod G, the jaws O C' are brought-together when the rod is revolved ,in one direction, and expanded when the movement of the rod is reversed.

The capacity of extension vand contraction of the clamps G C will be, of course, equal to the length of the rod G between the collars q y', less the ,width of projecting nuts F F. i

The sha e and dimensions oi' m device can be. Y c

variously modilied. I do not" claim, broadly, the jaw-arms sliding in a bed or frame; but

Vhat IV claim as my invention, and desire to secure by Letters Patent, is

A clamp, composed of jaw-arms C D, screw-rod G,

and box A, when constructed and arranged substantially as and for the purpose herein specified, shown, and described l -In testimony of which invention, I hereunto set my hand.

MATTHIAS G. BURKHARDT. Witnesses HERMAN MERRELL, E; E. WOOD.

grooves E 1Q gives strength to the shanks l) D', and locates the screw-rod G im- 

